A non-limiting example of such a system and corresponding therapy described in the present disclosure relates to patients with heart failure (HF), to which the implantation of a cardiac resynchronization device such as a CRT-P (pacemaker) or a CRT-D (pacemaker further provided with a defibrillator function) is proposed.
The therapy may aim to synchronize the contraction of both ventricles, and if necessary, those of the ventricles relative to the atrium in order to improve the patient's condition by optimizing the different phases of the hemodynamic cycle. The devices may implement a technique called “CRT” (Cardiac Resynchronization Therapy) or “BVP” (Bi-Ventricular Pacing) by issuing, as necessary, electrical pulses ensuring joint and permanent stimulation of both, left and right, ventricles to resynchronize the contractions of the latter.
The implantable device may include an endocardial pacing lead that is implanted in the right ventricle, and, for the stimulation of the left ventricle, a lead may be inserted into the coronary venous system via the coronary sinus, so as to place the stimulation electrode of the lead against the wall of the left ventricle. Alternatively, an epicardial lead may be introduced into the pericardial sac and secured to the outer wall of the heart muscle at the left ventricle. The device may also comprise a third lead positioned in the right atrial cavity, and may be used for detection of the contraction of the atrium in order to synchronize the stimulation of the ventricles in accordance with the chronology of the atrioventricular delay.
These endocardial or coronary leads may be introduced through the patient's venous system, which can create complications such as displacement, insulation or conductor breakdown, fibrosis development, etc.
To reduce these risks, a new generation of devices has been developed, which are in the form of implantable autonomous capsules for placement in a heart chamber (ventricle, atrium, or even arterial left heart chamber), and are usually designated as “leadless capsules”. These capsules are devoid of any physical connection to a main implantable device (such as the housing of a stimulation pulse generator) or non-implantable device (external device such as programmer or monitoring device for remote monitoring of the patient).
For this reason, they are referred to as “leadless” capsules, to distinguish them from electrodes disposed at the distal end of a conventional lead, traversed over its entire length by one or more conductors galvanically connecting the distal electrode to a connector located at the opposite, proximal end of the lead, said connector being intended to be connected to the housing of the pulse generator.
The WO2013/080038 A2 describes an example of such an endocardial or epicardial leadless capsule, and of its means of communication with the outside environment. The device also includes a pulse generator implanted subcutaneously, with a wired connection to an endocardial or epicardial electrode placed at a detection/stimulation site. The synchronization of the system is ensured by a wireless connection between the leadless capsules and the remote master generator.
The leadless capsules may replace the conventional endocardial leads, such as the right ventricular leads and/or the right atrial leads, or the epicardial leads, but because of the dimensions of the capsules, they may not be suitable substitutes for leads that pace the left ventricle, which are introduced into the coronary venous system. The left ventricular pacing leads may be needed for detection/stimulation of the left ventricle, and for the application of a CRT therapy.
In addition, the endocardial arterial network (providing access to the left cavities) remains at risk, even with a leadless capsule, because of the serious risk of bleeding or of blood clots, which can form arterial emboli.
On the other hand, as regards the left coronary leads, the need to use a guidewire for implantation, the standard for the multipolar left lead connectors (IS-4 or DF-4 standards) and the need for a central lumen formed in the lead body for introduction of the guide wire, are constraints that limit the ability to reduce the diameter of the coronary leads and therefore to reach new target areas for stimulation of the left ventricle that remain difficult to reach today.
Here the term “hybrid capsule” may be understood as including a device for the detection/stimulation of the left ventricle, comprising:                A body, which can be of the same shape and in the same configuration as a leadless capsule, with a low power consumption electronic architecture, a miniaturized power source and wireless communication means for communication with other capsules or external devices,        The body may include a lead directly extending from the body of the capsule without continuity solution (e.g., without intermediate connector or interface) so as to form an integral and fully autonomous device,        The lead may be a “Microlead”, that is to say a miniaturized lead of very small diameter (typically not more than 1 French, or 0.33 mm) and free of an internal lumen, formed of a conductive core cable coated with an insulating layer, and a distal region of the cable includes one or more selectively exposed areas forming detection/stimulation electrodes.        